Grinding machines having an essentially cylindrical grinding tool mounted on a vertical shaft protruding through a horizontal work table are commonly used for shaping pieces of glass used in making stained glass windows and the like. The piece of glass is supported on the surface of the work table and held against the rotating grinding tool by an artisan's hand to remove material from the edges of the piece of glass. Heat is generated in the grinding process, and it is therefore necessary to supply coolant to the grinding tool to keep it from over heating, as well as to wash away ground particles of glass.
Prior art grinders of this type supply coolant to the grinding tool by a sponge that is held against the surface of the grinding tool and rests in a reservoir of coolant beneath the work table. This method of supplying coolant to the grinding tool is economical, but it has several disadvantages. The sponges wear out from constant contact with the rotating grinding tool, and they can be knocked out of place. In addition, they do not always supply a sufficient quantity of coolant to the surface of the grinding tool. Furthermore, the surface of the sponge becomes clogged with glass particles and needs to be cleaned periodically.
Some prior art industrial grinding machines use various kinds of pumps to deliver coolant to the surface of the grinding tool, but these are usually more complicated and thus more expensive than is warranted for many applications. Other methods of directing a spray of coolant are also used for grinding tools that use a radial rather than an axial or circumferential surface of the tool for grinding. However, it is often easier to deliver coolant to a radial face of a rotating tool than to an axial face as is required with the subject grinding apparatus.